GEOLOGY

Detailed explanation-1: -This is because there is more salt packed into the water. High temperature makes water less dense. As water gets warmer, its molecules spread out, so it becomes less dense.

Detailed explanation-2: -The surface layer is the top layer of the water. This layer is also known as the mixed layer and is well stirred from the wind and other forces. This top ocean layer tends to be the warmest layer due to heating from the sun.

Detailed explanation-3: -The main source of ocean heat is sunlight. Additionally, clouds, water vapor, and greenhouse gases emit heat that they have absorbed, and some of that heat energy enters the ocean. Waves, tides, and currents constantly mix the ocean, moving heat from warmer to cooler latitudes and to deeper levels.

Detailed explanation-4: -AAIW means Antarctic Intermediate Water. It originates in the oceans north of Antarctica at about 55°S latitude and descends down below the surface waters of the Atlantic, Pacific, and Indian Oceans. It sits atop all the other thermohaline currents, which means it must be the least dense.

Detailed explanation-5: -The density of seawater depends on temperature and salinity. Higher temperatures decrease the density of seawater, while higher salinity increases the density of seawater.